Valve mechanism for internal-combustion engines.



w. TWOMBLY.

VALVE MECHANISM FOR INTERNAL COMBUSTION ENGINES. APPLICATION FILED AUG. 12. I914.

I,33,6 I" Patented July 17, 1917.

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VALVE MECHANISM FOR INTERNAL COMBUSTION ENGINE S. APPLICATION FILED AUG-I2, 1914.

1,233, 21 Patented July 17, 1917. Y

4 SHEETS-SHEET 2- v W. I. TWOMBLY.

VALVE MECHANISM FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED AUG I2| 19M. 7

Patented July 17, 1917.

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'mwyf APPLICATION FILED AUG-l2. 1914.

vPatented July 17, 1917.

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M Ward 11 1i rain PATET Uh l ltlm WILLARD IRVING TWOMIBLY, OF NEW YORK, N. Y'., ASSIGNOR, BY MESNE ASSIGN- MENTS, TO HENRY W.'JESSUP, TRUSTEE, OF NEW YORK, N. Y.

VALVE MECHANISM FOR INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent.

Patented'el uly 1'7, 191?.

Application filed. August 12, 1914. Serial No. 856,318.

To all whom it-mag concern:

Be it known that I, l/VILLARD IRVING- TwoMBLY, a citizen of'the United States, residing in the borough of Manhattan, in the city, county,and State of New York, have invented new and useful Improvements in Valve Mechanism for Internal- Combustion Engines, of which the following is a specification.

This invention relates to internal combustion engines of the four cycle type wherein there is imparted to the piston a'power stroke upon alternate revolutions. of the power shaft, and relates particularly to this type of engines in which the charge of fuel to and the exhaust from the cylinder is controlled by a valve through a single port in the cylinder, and it is the object of the present invention to simplify the construction'and operation of engines of this type and at the same time increase the efficiency thereof,

A further object of the invention relates to an improved piston or slide valve'mechanism'to control the opening and closing of the cylinder port. To actuate this type of valVemechanism it has heretofore beenthe practice to operate the valve by a cam or cams on a shaft driven from the power shaft at one half the speed of said power shaft, 'or through eccentrics mounted on the one half speed shaft In carrying out this feature of theinve, tion I provide a cam on the power shaft to rotate at the same speed-"as said shaft and connect the valve to said cam, said cam imparting a toand-fro reciprocatory movement to the piston valve during two revolutions of the power shaft in such a manner as to insure a quick opening and closing of the cylinder port in proper timed relation with the movements of the piston. I,

Another object of the invention relates to an improved valve operating cam and the means to connect the valve with the cam, said cam comprising a disk having a raceway in one face consisting of intersecting grooves of channel section, with the exception of one of the intersecting; portions of the grooves which is of T-shape and of greater depth than the other intersecting and-remaining portion of the grooves, a cam follower connected to the valve engaging in said grooves. In the present instance the cam follower is in the nature of a roller having a shank, and to connect the valve with the cam follower I provide a pivotally supported arm in which the shank of the roller is mounted to have. rotative and axial movement, a rod connecting the valve with said arm. By this construction any tendency of the cam to drag the roller along with it as it is rotated with the consequent lateral strain on the valve connecting rod is entirely obviated. To cause the roller to engage in the T-shaped portion of the cam grooves I provide a cam on the power shaft adapted to engage with the end of the shank of the cam roller at predetermined points in and upon alternate revolutions of the shaft.

Other objects and advantages will hereinafter appear. i

As a preface to a description of the construction and operation of my improved engine, I wish to state that while I have illustrated and will describe. the same in connection with an engine of the stationary type having a pair of opposed cylinders, it

is to be understood. that it will work as efli ciently as a-single cylinder engine, or a series of radially projecting cylinders may be employed and the valves for all of the cylinders controlled by a single cam; or that the crank haft may be fixed and the cylinders and piston mechanism rotated about said shaft. a

In the drawings accompanying and forming a part of this specification, Figure 1 is a sectional side elevation of an opposed cylinder engine illustrating an embodiment of my invention.

Fig. 2 is. an end elevation, looking at the right of Fig. 1, partly in section, with a portion of the case removed to illustrate the cam and the connection of the valves thereto.

Fig. 3 is a sectional side elevation of the cam following roller and its connection to the valve Fig. 4 is a perspective view of the cam to cause the cam follower to engage in the T-shaped portion of the cam grooves;

Fig. 5 is a side elevation of the 'valve' operating cam. a

Fig. 6 is a sectional side elevation of the cam taken on the line AA of Fig. 5.

Fig. 7 is a sectional side elevation ofthe valve and valve chamber.

Fig. 8 is a plan view, partly broken away, of the valve and the valve chamber.

Fig. 9 is a disassembled side elevation of a modified cam follower; and

Figs. 10 to 17, inclusive, are dlagrammatic views to illustrate the positions of the valve. relative to the piston in the reciprocation of the latter during the four cycles of operation.

Similar characters of reference desi ate like parts throughout the different views of the drawings. a V

The embodiment of my invention illustratd in the drawings comprises a crank case, (designated in a general Way by 0,)

said casing having lateral concentric walls 18 and 19, providing two separate chambers 20 and 21, the outer ends of which are closed by a plate or cover 22 secured to the casing by. bolts 23. The chamber 20 constitutes a fuel chamber connected at 20' to the source of fuel supply through a carbureter, not shown. A single throw crank shaft 2% is journaled in the casing, in the present instance by means of ball bearings, a projecting end of said shaft extending through and journaled in the cover plate 22. A pair of opposed piston cylinders 25 engage in openings in the crank case and are secured thereto by bolts and clamping members, the latter engaging over a flange projecting laterally from the cylinders, as shown at 26. Pistons 27 provided with the usual packing rings and oil grooves are adapted to work in the cylinders and 'are connected to the crank pin of the shaft by rods 28.

The charge of fuel to, and the exhaust of the burnt gases from. the cylinders are controlled through a single port 29 in each cylinder. in the present instance located in a laterally projecting portion of removable cylinder heads 30 having screw threaded connection with the cylinders 25.

To control the charge of fuel to,'and the exhaust of the burnt gases from, the cylinders throughthe ports 29, I provide piston valves, designated in a general way by P, adapted to reciprocate in valve chambers 31 with which the cylinder ports 29 communicate. These valve chambers are cylindrical in form, and in the present instance constructed integral with the cylinder of said valve chambers.

heads. The charge of fuel and exhaust is controlled from opposite ends ofthe valve chambers, and the cylinder ports are adapted through the valves to be alternately placed in communication with opposite ends The end of the valve chambers through which the fuel is controlled is connected to the fuel chamber 20 in the crank case by tubular mem-v bers 38, one end of which engage in openings in said latter chamber and the other ends having a telescoping connection with the valve chambers.

The valves each consist of a pair of axially. separable sections 32 and 33, the section 33 having a sleeve portion provided with ports 34 to connect the cylinder port 29 with one end of the valve chamber to admit a charge of fuel to the cylinder. Interposed between the sections 32 and 33 is an angular ring 35 of the same diameter as said sections. The sections 32 and 33 are so constructed as to provide in conjunction with said ring angular recesses for the reception of packing rings 36, the whole being maintained in assembled position by a headed bolt 37.

The valve chambers are each provided with a laterally projecting portion 391in which is located a chamber which is connected to the cylinder port 29, and practically constitutes a continuation thereof. By the provision of this chamber any compression pressures in the cylinders tending to exert a lateral pressure on that side of the valve and adjacent to the port 29, and

. or a two-way cam raceway in one face thereof. The cam is located on the shaft to operate in the chamber 21 to which lubricant may be supplied to constitute a lubricant containing housing for the cam.

Cam followers 42 engaging in the raceway, comprise rollers each having a shank 43 whereby they are carried by arms 44 pivotally supported, as at 451 to have rotative and axial movement. To facilitate the travel of the rollers in the cam groove the side opposite the shank is slightly rounded, as clearly shown in Fig. 3. The cam followers are connected to the valves through links 46 pivotallvconnected at one end to the arm 44 (Fig. 3) and at the other ends to cross heads 47 slidably mounted in boxes 48 fixed mas er in the wall 19, rods 49 pivotally connected at opposite ends to the valves and crossheads connecting the valves to the latter. By connecting the valves to the cam through the cross-heads any liability of lateral pressure on the valves is obviated.

As already stated the cam 41 comprises a disk having a two-way cam groove in one the portion 6 and crosses over intothepor tion a. To overcome this disadvantage T construct the cam raceway from substan-' tially the point eto the point f of greater depth than the remaining portion of the raceway and substantially of inverted 'l'- shape, with the remaining portion between the points 0 and a substantially of channel shape. By this construction not only is the binding of its shank in the carrier. Fur

thermore, when the roller engages in the shallow portion of the raceway the said face will be flush with the link 46 and prevents any canting action of theroller when in said shallow portion. To cause the cam follower to engage in the T-shaped portion of the raceway I provide a cam 50 on the crank shaft to rotate therewith, the working portion 51 of which cam is adapted to engage with the end of the roller shank upon alternate revolutions of the shaft, and which working portion is of the same inclination as the portion 6 of the raceway where the channel portion merges with the IF-shape portion from a toe.

As stated the engine is of the four cycle type in which, (assuming the piston to be in tit sive,l have illustrated in a diagrammatic manner the relative positions of the valve,

the valve-operating cam and piston during these four cycles of operation. -With the piston in the position shown in Fig. 1 and a compressed charge of fuel in the cylinder the valve mechanism will assume the position in said figure with communication shut off between the cylinder port 29 and the valve chamber, and with the cam follower engaging in the outercanr groove a in sub stantially the position indicated by radial line 9, Fig. 5. During the power stroke of the piston or initial 180 degrees of revolution of the crank shaft the cylinder portwill' be maintained closed by the valve, the cam follower crossing over into the inner 4 cam groove and assuming the position indicated by the radial line it. The piston, valve and cam are now in the positions indicated in Fig. 10. However, just previous to the piston approaching the" end of its power stroke motion will be imparted to the valve and the valve will commence to uncover the port 29 to connect it with the exhaust end of the valve chamber. During-the travel of the cam the distance between the radial lines it and i (Fig. 5) and during the initial portion of the exhaust stroke of the piston a quick motion will be imparted tothe valve entirely uncovering the port 29 and the valve will assume the position indicated in Fig. 11. The cam-follower roller is now engaging in the inner groove 2) and during the travel of the cam from substantially the radial line m to the radial line i the cam 50 on the crank shaft will engage with the end of the roller shank and cause the roller to radial line 3', the port 29 will be maintained uncovered by the valve, but as the piston ap-. proaches the end of the exhaust stroke and the cam travels the distance between the radial'lines j and g, motion will be imparted to the valve and theparts assume the position indicated in Fig. 12, and'as the cam reaches the position indicated by radial line 9 and the pistonh'as reached the end of its.

exhaust stroke, the valve will entirely cove the port 29 and the parts assume the positionsindicated in Fig. 13. During the continued rotation of the crank shaft and the initial portion of the suction stroke of the ered and at the point 70 the ports 34 in the valve will commence to register with said &

' port 29, the cam follower crossing over into a the valve and the parts assume the position indicated in Fig. 16. This movement of the valve will continue during the latter portion of the suction stroke of the piston and during the travel of the cam the distance between the radial lines 'm and h when the ports will be in the position indicated in Fig. 17 with the port 29 entirely closed and the piston about to commence its fuel compression stroke. During the initial portion of the fuel compression stroke of the piston the valve will continue to move downward for a slight distance until it is in the position indicated in Fig. 1 in which position it will remain during the fuel compression stroke of the piston and during the travel of the cam substantially the distance between the lines h and 9, it being remembered that the cam follower is now engaging in the outer cam groove (1, .when the cycle of operations will be repeated.

The cam-following roller maybe made of an integral metal structure if desired, as shown in Fig. 3. I have, however, shown in Fig. 9 a modified construction of cam roller comprising a metallic shank or stem 51 having an annular flange or shoulder 52 adjacent one end, a fiber disk 53 beingadapted to engage on the end of said shank and abut against the flange and maintained thereon by a washer 54, the end of the shank being turned or riveted over toclamp the fiber disk between the washer and shank flange. Byuse of such a roller all noise due to knocking is entirely obviated.

The present engine as illustrated is of the air cooled type and for this purpose the cylinder head is provided with integral cooling fins or ribs 55. The cylinders are provided with removable fins 56 consisting of a plurality of superposed annular sheet metal members, preferably of copper, said members having an annular flange portion to lie adjacent the cylinder and which serve to space the fins apart. The lowermost fin rests upon an annular shoulder or flange on the outer surface ofthe cylinder, and the fins clamped in superposed position as the head is screwed on to the cylinder. The fins are preferably'crimped or corrugated to provide a greater cooling surface.

I do not wish to be understood as limiting my invention to the features of construction herein shown and described, since the general construction and arrangement may be varied without departing from the spirit of my invention. There are other features of the invention which I regard as particularly novel, as, for instance, the construction of the cam and the connection of the cam with the reciprocable member.

While I have shown and described the cam as fixed on the power shaft of an engine to actuate a piston or slide valve to control the charge of fuel to and the exhaust from an engine cylinder, it is to be understood that I do not limit the invention to the particular relationshown as it may be employed in various apparatus to convert rotary motion into reciprocating motion, in which it is essential that a toand-fro movement is imparted to a reciprocable member during every two revolutions of the rotating member.

Variations may be resorted to within the scope of my invention.

Having thus described my invention, I

claim: I 1. In a four cycle internal combustion engine, the combination with a crank shaft, of a cylinder having a port; a piston valve to control the charge of fuel to and the exhaust from the cylinder through said port; and a cam fixed on the crank shaft to reciprocate the valve, comprising a disk having an intersecting raceway in one face thereof, said raceway being substantially of channel shape with one of the intersecting portions of greater depth and T-shaped.

'2. In a four cycle internal combustion engine, the combination with a crank shaft, of a cylinder having a port; a piston valve to control the charge of fuel to and the exhaust from the cylinder through said port; a cam fixed on the crank shaft to reciprocate the valve, comprising a disk having an intersecting raceway in one face thereof, said raceway being substantiallychannel shaped with one of the intersecting portions of the raceway of T-shape and of greater depth than the other intersecting and remaining portion of the raceway, and a roller connected to the valve adapted to engage in the raceway.

3. In a four cycle internal combustion engine, the combination with a crank; shaft,

' of a cylinder having a port; a 'reciprocable valve to open and close said port to control the chargeof fuel to and the exhaust from the cylinder through said port; a cam fixed on and rotatable at the same speed as the crank shaft to reciprocate the valve, com prising a disk having an intersecting raceway in one face thereof, said raceway being substantially channel shaped with one of the intersecting portions of the raceway of IF-shape and of greater depth than the other intersecting and remaining portion of the raceway; a roller having a shank adapted to engage in said raceway; a pivotally supported arm to carry said roller to have rotative and axial movement; and a rod connected to the valve and arm to connect the valve to the cam following-roller.

4. In a four cycle internal combustion engine, the combination with a crank shaft, of a cylinder having a port; a piston valve to control the charge of fuel to and the exhaust from the cylinder through said port; a cam fixed on the crank shaft to reciprocate the valve, comprising a disk having an intersecting raceway in one face thereof, said raceway being substantially of channel shape with one of the intersecting portions of the raceway'of T-shape and of greater depth than the other intersecting and remaining portion of the raceway; a roller having a shank adapted to engage in said raceway; a pivotally supported arm to carry said roller to have rotative and axial movement; a rod connected to the valve and arm to connect the valve to the cam-following roller; and means to engage with the-shank of the cam-following roller to cause the roller to engage in the T-shaped portion of the raceway,

5. The combination with a reciprocable member and a continuously rotating shaft, of a cam fixed to and rotatable with the shaft to impart a to-and-fromovement to the reciprocable member during two revolutions of the shaft and cam, said cam comprising a disk having a pair of intersecting grooves in one face thereof, with the intersecting portions of one groove of T-shape and the remaining portion of the groove of channel shape; a cam following roller having a shank to engage in the cam groove; and means to connect the reciprocable member to the cam following roller.

6. The combination with a reciprocable member and a continuously rotating shaft, of a cam fixed to and rotatable with the shaft to impart a to-and-fro movement to the reciprocable member during two revolutions of theshaft and cam, said cam com-' prising a disk having a pair of intersecting grooves in one face thereof, with the intersecting portions of one groove of T-shape and the remaining portion of the groove of channel shape; a cam following roller having a shank to engage in the cam groove; and means to connect the reciprocable member to the cam following roller, comprising a pivotally supported arm in which the shank of the cam following roller is mounted to/ have rotative and axial movement, and a rod connected to the reciprocable member and said arm. A

7. The combination with a receiprocable member and a continuously rotating shaft, of a cam fixed to and rotatable with the shaft to impart a to-and fro movement to the reciprocable member during two revolutions of the shaft and cam, said cam comprising a disk having a pair of intersecting grooves in one face thereof, with the intersecting portion of one groove of' T-shape and the remaining portion of the groove of channel shape; a cam following roller having a shank to engage in the cam groove; and means to connect the reciprocable member to the cam following roller, comprising a pivotally supported arm in which the shank of the cam following roller is mounted to have rotative and axial movement, and a rod connected to the reciprocable member and said arm; and a cam on the shaft adapted to engage with the shank of the cam following roller to cause it to engage in the IF-shaped portion of the cam groove. 1

8. A cam comprising a disk having a raceway in one face thereof consisting of an intersecting groove, with one intersecting portion of the groove of T-shape and the remaining portion of the groove of channel shape, and of less depth than the T-shaped portion of the groove.

W. IRVING TWOMBLY. Witnesses:

PAULA PIIILIPP, LAURA E. SMITH. 

